WO2023132010A1

WO2023132010A1 - Air-conditioning device

Info

Publication number: WO2023132010A1
Application number: PCT/JP2022/000097
Authority: WO
Inventors: 亮宗石村
Original assignee: 三菱電機株式会社
Priority date: 2022-01-05
Filing date: 2022-01-05
Publication date: 2023-07-13
Also published as: JPWO2023132010A1

Abstract

This air-conditioning device comprises a refrigerant circuit in which a compressor, a heat-source-side heat exchanger, a throttling device, and a load-side heat exchanger are connected in the stated order by piping, a non-azeotropic mixed refrigerant being sealed inside the refrigerant circuit as a refrigerant, wherein the air-conditioning device also comprises: a first pressure detection device for detecting the pressure of the refrigerant on the discharge side of the compressor, or detecting the pressure of the refrigerant on the intake side of the compressor; an outside air temperature detection device for detecting the temperature of outside air; and a control device having a refrigerant leak detection function for assessing whether a refrigerant leak has occurred, when the air-conditioning device stops, on the basis of the pressure detected by the first pressure detection device and the outside air temperature detected by the outside air temperature detection device.

Description

air conditioner

The present disclosure relates to air conditioners applied to multi-air conditioners for buildings and the like.

Conventionally, in air conditioners such as multi air conditioners for buildings, for example, an outdoor unit, which is a heat source unit arranged outside the building, and a plurality of indoor units arranged inside the building are connected with refrigerant pipes to form a refrigerant circuit. to circulate the refrigerant. In some cases, the total length of the refrigerant pipes connecting the outdoor unit and the plurality of indoor units is several hundred meters, and accordingly the amount of refrigerant used is extremely large. Therefore, in order to prevent a large amount of refrigerant from being released into the atmosphere when a refrigerant leak occurs from an air conditioner, a technique has been proposed for estimating the presence or absence of refrigerant leakage from the operating state of the air conditioner. (See Patent Document 1, for example).

WO2009/157200

However, with the technology disclosed in Patent Document 1, it is necessary to set the operation mode to the cooling operation mode, and refrigerant leakage cannot be determined in the interim period when the air conditioner is not operated or in the winter when the heating operation is performed. I had a problem.

The present disclosure has been made to solve the above problems, and provides an air conditioner that can detect the occurrence of refrigerant leakage from the air conditioner regardless of the operating state of the air conditioner. It is an object.

An air conditioner according to the present disclosure includes a refrigerant circuit in which a compressor, a heat source side heat exchanger, a throttle device, and a load side heat exchanger are connected in order by piping, and non-azeotropic refrigerant is used as a refrigerant in the refrigerant circuit. An air conditioner in which mixed refrigerant is sealed, comprising: a first pressure detection device for detecting the pressure of the refrigerant on the discharge side of the compressor or the pressure of the refrigerant on the suction side of the compressor; An outside air temperature detection device for detecting temperature, and when the air conditioner is stopped, the presence or absence of refrigerant leakage is detected based on the pressure detected by the first pressure detection device and the outside air temperature detected by the outside temperature detection device. and a control device having a refrigerant leakage detection function for performing determination.

According to the air conditioner according to the present disclosure, when the air conditioner is stopped, the presence or absence of refrigerant leakage is determined based on the pressure detected by the first pressure detection device and the outside temperature detected by the outside temperature detection device. conduct. Therefore, refrigerant leakage can be detected throughout the year regardless of the season, and the occurrence of refrigerant leakage from the air conditioner can be detected regardless of the operating state of the air conditioner.

1 is a schematic configuration diagram showing an example configuration of an air conditioner according to an embodiment; FIG. 1 is a refrigerant circuit diagram showing an example of a circuit configuration of an air conditioner according to an embodiment; FIG. FIG. 3 is a refrigerant circuit diagram showing the flow of refrigerant during cooling operation of the air conditioner according to the embodiment. FIG. 4 is a refrigerant circuit diagram showing the flow of refrigerant during heating operation of the air conditioner according to the embodiment. 4 is a flow chart showing the operation of the refrigerant leakage detection function of the air conditioner according to the embodiment.

Hereinafter, embodiments of the present disclosure will be described based on the drawings. It should be noted that the present disclosure is not limited by the embodiments described below. Also, in the following drawings, the size relationship of each component may differ from the actual size.

Embodiment 1.
FIG. 1 is a schematic configuration diagram showing an example configuration of an air conditioner 100 according to an embodiment.
The configuration of the air conditioner 100 according to Embodiment 1 will be described below with reference to FIG.

The air conditioner 100 according to the embodiment uses 68.9 [wt%] and 31.1 [wt% ] is circulated in the refrigerant circuit (see FIG. 2 to be described later) to perform air conditioning using the refrigeration cycle. Further, the air conditioner 100 can select a cooling only operation mode in which all indoor units are operated for cooling or a heating only operation mode in which all indoor units are operated for heating, such as a multi air conditioner for buildings. As shown in FIG. 1, the air conditioner 100 includes one outdoor unit 1 and two

indoor units

2a and 2b. They are connected by a refrigerant main pipe 3 and

refrigerant branch pipes

4a and 4b. The

indoor units

2a and 2b are installed in air-conditioned

spaces

60a and 60b, respectively. In the embodiment, as shown in FIG. 1, the number of outdoor units 1 is one and the number of

indoor units

2a and 2b is two. Alternatively, the number of

indoor units

2a and 2b may be one or three or more.

FIG. 2 is a refrigerant circuit diagram showing an example of the air conditioner 100 according to the embodiment.
As shown in FIG. 2, the air conditioner 100 includes a refrigerant circuit through which refrigerant flows. The refrigerant circuit includes a compressor 10, a refrigerant flow switching device 11, a heat source side heat exchanger 12, expansion devices 41a and 41b, load side heat exchangers 40a and 40b, and an accumulator 13. It is configured to be connected by pipes including

branch pipes

4 a and 4 b and refrigerant pipe 5 .

[Outdoor unit 1]
The outdoor unit 1 includes a compressor 10 , a refrigerant flow switching device 11 , a heat source side heat exchanger 12 and an accumulator 13 . In addition, a heat source side blower 14 configured by, for example, a fan is provided near the heat source side heat exchanger 12 , and the heat source side blower 14 blows air to the heat source side heat exchanger 12 . Compressor 10 , refrigerant flow switching device 11 , heat source side heat exchanger 12 , and accumulator 13 are connected by refrigerant pipe 5 .

The compressor 10 draws in a low-temperature, low-pressure refrigerant and compresses the refrigerant to a high-temperature, high-pressure state. The refrigerant flow switching device 11 is, for example, a four-way valve, and switches between refrigerant flow in the cooling operation mode and refrigerant flow in the heating operation mode.

The heat source side heat exchanger 12 functions as a condenser in the cooling operation mode and as an evaporator in the heating operation mode, and performs heat exchange between the air supplied from the heat source side blower 14 and the refrigerant. .

The accumulator 13 is provided on the suction side of the compressor 10, and is used to store surplus refrigerant caused by the difference in operating conditions between the cooling operation mode and the heating operation mode, or surplus refrigerant due to transient changes in operation. It is.

The outdoor unit 1 also includes a discharge pressure detection device 20 and a suction pressure detection device 21 . The discharge pressure detection device 20 is provided in the refrigerant pipe 5 that connects the discharge side of the compressor 10 and the refrigerant flow switching device 11, and detects the pressure of the high-temperature, high-pressure refrigerant on the discharge side of the compressor 10. be. The suction pressure detection device 21 is provided in the refrigerant pipe 5 that connects the refrigerant flow switching device 11 and the suction side of the compressor 10, and detects the pressure of the low-temperature, low-pressure refrigerant on the suction side of the compressor 10. It is. The discharge pressure detection device 20 and the suction pressure detection device 21 are, for example, pressure sensors.

In addition, the outdoor unit 1 includes an outside air temperature detection device 22 and a first temperature detection device 23. The outside air temperature detection device 22 is provided in an air intake portion (not shown) of the outdoor unit 1, and detects the air temperature (hereinafter referred to as the outside air temperature) at the location where the outdoor unit 1 is installed. be. The first temperature detection device 23 is provided in the refrigerant pipe 5 that connects the discharge side of the compressor 10 and the refrigerant flow switching device 11, and detects the temperature of the high-temperature and high-pressure refrigerant on the discharge side of the compressor 10 (hereinafter referred to as the discharge temperature). The outside air temperature detection device 22 and the first temperature detection device 23 are, for example, thermistors.

[

Indoor units

2a, 2b]
The

indoor units

2a and 2b respectively include load-side heat exchangers 40a and 40b and expansion devices 41a and 41b. In addition, load-side blowers 42a and 42b composed of, for example, fans are provided near the load-side heat exchangers 40a and 40b. to blow air. The

indoor units

2a and 2b are connected to the outdoor unit 1 via a refrigerant main pipe 3, so that refrigerant flows in and out. The load-side heat exchangers 40a, 40b exchange heat between the air supplied from the load-side fans 42a, 42b and the refrigerant, and generate heating air or cooling air to be supplied to the indoor space. is. The expansion devices 41a and 41b function as pressure reducing valves or expansion valves, and reduce the pressure of the refrigerant to expand it. do it.

The

indoor units

2a and 2b are provided with second temperature detection devices 50a and 50b, third

temperature detection devices

51a and 51b, and fourth

temperature detection devices

52a and 52b, respectively. The second temperature detection devices 50a and 50b are provided in the

refrigerant branch pipes

4a and 4b that connect the expansion devices 41a and 41b and the load side heat exchangers 40a and 40b, and detect the load side heat exchangers 40a and 40b in the cooling operation mode. It detects the temperature of the coolant flowing into 40b. The third

temperature detection devices

51a and 51b are provided in the

refrigerant branch pipes

4a and 4b on the opposite side of the expansion devices 41a and 41b with respect to the load side heat exchangers 40a and 40b. It detects the temperature of the refrigerant flowing out of the exchangers 40a and 40b. The

fourth temperature detectors

52a, 52b are provided in the air intake portions (not shown) of the load-side heat exchangers 40a, 40b, and detect the indoor air temperature. The second temperature detection devices 50a, 50b, the third

temperature detection devices

51a, 51b, and the fourth

temperature detection devices

52a, 52b are, for example, thermistors.

In the following, the

indoor units

2a and 2b, the load-side heat exchangers 40a and 40b, the expansion devices 41a and 41b, and the load-side fans 42a and 42b are collectively referred to as the indoor unit 2 and the load-side heat exchanger 40, respectively. , an expansion device 41 and a load-side blower 42 . Further, the second temperature detection devices 50a and 50b, the third

temperature detection devices

51a and 51b, and the fourth

temperature detection devices

52a and 52b are collectively referred to as the second temperature detection device 50, the third temperature detection device 51, and a fourth temperature detection device 52 . Also, one of the discharge pressure detection device 20 and the suction pressure detection device 21 is also called a first pressure detection device. The discharge pressure detection device 20 and the suction pressure detection device 21 are collectively referred to as a pressure detection device.

The air conditioner 100 also includes a control device 30 configured by a microcomputer or the like. The control device 30 determines the frequency of the compressor 10, the number of rotations of the heat source side blower 14 of the heat source side heat exchanger 12 (the heat source side blower 14 ON/OFF ), the switching of the refrigerant flow switching device 11, the opening degree of the expansion device 41, and the like, and each operation mode, which will be described later, is executed. In addition, in the embodiment, as shown in FIG. 2, an example in which the control device 30 is provided in the outdoor unit 1 is shown, but the present invention is not limited to this. The control device 30 may be provided in the indoor unit 2 or may be provided in both the outdoor unit 1 and the indoor unit 2 .

[Cooling operation mode]
FIG. 3 is a refrigerant circuit diagram showing the flow of refrigerant in the cooling operation mode of the air conditioner 100 according to the embodiment. In addition, in FIG. 3, the flow direction of the refrigerant is indicated by solid arrows.
Hereinafter, the cooling operation mode of the air conditioner 100 according to the embodiment will be described with reference to FIG.

In the cooling operation mode, the refrigerant flow switching device 11 is switched so that the refrigerant discharged from the compressor 10 flows into the heat source side heat exchanger 12 . Then, the low-temperature, low-pressure refrigerant is compressed by the compressor 10 and discharged as a high-temperature, high-pressure gas refrigerant. The high-temperature, high-pressure gas refrigerant discharged from the compressor 10 flows through the refrigerant flow switching device 11 into the heat source side heat exchanger 12 . The high-temperature, high-pressure gas refrigerant that has flowed into the heat source side heat exchanger 12 is condensed while radiating heat to the outdoor air, and becomes a high-pressure liquid refrigerant. The high-pressure liquid refrigerant that has flowed out of the heat source side heat exchanger 12 flows out of the outdoor unit 1, passes through the refrigerant main pipe 3 and the

refrigerant branch pipes

4a, 4b, and flows into the

indoor units

2a, 2b.

The high-pressure liquid refrigerant that has flowed into the

indoor units

2a and 2b is decompressed by the expansion devices 41a and 41b into low-temperature and low-pressure two-phase refrigerant, and then flows into the load-side heat exchangers 40a and 40b that act as evaporators. By absorbing heat from the air, it cools the indoor air and becomes a low-temperature, low-pressure gas refrigerant. The low-temperature, low-pressure gas refrigerant flowing out of the load-side heat exchangers 40 a and 40 b flows into the outdoor unit 1 through the

refrigerant branch pipes

4 a and 4 b and the refrigerant main pipe 3 . The refrigerant that has flowed into the outdoor unit 1 passes through the refrigerant flow switching device 11 and the accumulator 13 and is sucked into the compressor 10 .

Here, the degree of opening of the throttling devices 41a and 41b is superheat ( The degree of superheat) is controlled by the controller 30 so as to be constant. By doing so, the capacity corresponding to the heat load in the room can be exhibited, and efficient operation can be performed.

[Heating operation mode]
FIG. 4 is a refrigerant circuit diagram showing the flow of refrigerant in the heating operation mode of the air conditioner 100, and the direction of refrigerant flow is indicated by solid arrows. In addition, in FIG. 4, the flow direction of the refrigerant is indicated by solid arrows.
The heating operation of the air conditioner 100 according to the embodiment will be described below with reference to FIG. 4, taking as an example a case where a thermal load is generated in the load-side heat exchangers 40a and 40b.

In the heating operation mode, the refrigerant flow switching device 11 is switched so that the refrigerant discharged from the compressor 10 flows into the load side heat exchangers 40a and 40b. Then, the low-temperature, low-pressure refrigerant is compressed by the compressor 10 and discharged as a high-temperature, high-pressure gas refrigerant. The high-temperature, high-pressure gas refrigerant discharged from the compressor 10 passes through the refrigerant flow switching device 11, the main refrigerant pipe 3 and the

refrigerant branch pipes

4a, 4b, and flows into the

indoor units

2a, 2b. The high-temperature, high-pressure gas refrigerant that has flowed into the

indoor units

2a, 2b radiates heat to the indoor air in the load-side heat exchangers 40a, 40b, becomes high-pressure liquid refrigerant, and flows into the expansion devices 41a, 41b. After being decompressed into a low-temperature, low-pressure two-phase refrigerant by the expansion devices 41a and 41b, the refrigerant flows out of the

indoor units

2a and 2b, passes through the

refrigerant branch pipes

4a and 4b and the refrigerant main pipe 3, and flows into the outdoor unit 1.

The low-temperature, low-pressure two-phase refrigerant that has flowed into the outdoor unit 1 flows into the heat source side heat exchanger 12 and absorbs heat from the outdoor air to become a low-temperature, low-pressure gas refrigerant. The low-temperature, low-pressure gas refrigerant that has flowed out of the heat source side heat exchanger 12 passes through the refrigerant flow switching device 11 and the accumulator 13 and is sucked into the compressor 10 .

Here, the degree of opening of the expansion devices 41a and 41b is the difference between the saturated liquid temperature of the refrigerant calculated from the pressure detected by the discharge pressure detection device 20 and the temperature detected by the second temperature detection devices 50a and 50b. It is controlled by the control device 30 so that the subcooling (degree of supercooling) obtained as is constant. By doing so, the capacity corresponding to the heat load in the room can be exhibited, and efficient operation can be performed.

[Refrigerant leak detection function]
Next, the refrigerant leakage detection function will be described. The refrigerant leakage detection function is one of the functions of the control device 30, and when the air conditioner 100 is in a stopped state, the detection value of the pressure detection device mounted on the outdoor unit 1 and the detection value of the outside air temperature detection device 22 It is a function to detect the presence or absence of refrigerant leakage based on the value.

FIG. 5 is a flow chart showing the operation of the refrigerant leakage detection function of the air conditioner 100 according to the embodiment.
The operation of the refrigerant leakage detection function of the air conditioner 100 according to the embodiment will be described below with reference to FIG.

(Step S1)
Control device 30 determines whether air conditioner 100 is in a stopped state. Here, the state in which the air conditioner 100 is stopped means a state in which the compressor 10 is stopped. When control device 30 determines that air conditioner 100 is in a stopped state (YES), the process proceeds to step S2. On the other hand, when the control device 30 determines that the air conditioner 100 is not in the stopped state (NO), the process repeats step S1.

(Step S2)
The control device 30 determines whether or not a predetermined period of time (hereinafter, also referred to as a preset first period of time) has elapsed since the air conditioner 100 was stopped. Here, the control device 30 has a timer function for measuring time. When the control device 30 determines that the air conditioner 100 has been stopped and the predetermined time or longer has passed (YES), the process proceeds to step S3. On the other hand, when the control device 30 determines that the air conditioner 100 has been stopped and the predetermined time or longer has not elapsed (NO), the process returns to step S1. Although the control device 30 has a timer function in the embodiment, it is not limited to this, and a real-time clock or the like may be provided outside the control device 30, for example.

(Step S3)
The control device 30 determines whether the outside air temperature detected by the outside air temperature detection device 22 is stable. Here, whether or not the outside air temperature detected by the outside temperature detection device 22 is stable is determined, for example, by whether the outside temperature detected by the outside temperature detection device 22 is within a predetermined range for a predetermined period of time. based on When the control device 30 determines that the outside air temperature detected by the outside air temperature detection device 22 is stable (YES), the process proceeds to step S4. On the other hand, when the control device 30 determines that the outside air temperature detected by the outside air temperature detection device 22 is not stable (NO), the process returns to step S1.

(Step S4)
The control device 30 calculates the saturation temperature of the refrigerant from the detection value of the discharge pressure detection device 20 . In non-azeotropic refrigerant mixtures, the saturated vapor temperature and saturated liquid temperature at the same pressure are different, so the definition of which saturation temperature to use or the average value of those two saturation temperatures should be clarified. need to keep Any of the saturated vapor temperature, the saturated liquid temperature, and the average value of these two saturated temperatures may be used in the stop-time refrigerant leakage function according to the embodiment. In the above description, the discharge pressure detection device 20 is used to calculate the saturation temperature of the refrigerant. good too.

(Step S5)
The control device 30 determines whether the difference between the refrigerant saturation temperature calculated in step S4 and the outside air temperature detected by the outside air temperature detection device 22 is equal to or greater than a predetermined value. When control device 30 determines that the difference between the refrigerant saturation temperature and the outside air temperature is equal to or greater than the predetermined value (YES), the process proceeds to step S6. On the other hand, when control device 30 determines that the difference between the saturation temperature of the refrigerant and the outside air temperature is not equal to or greater than the predetermined value (NO), the process returns to step S1.

(Step S6)
The control device 30 determines that refrigerant leakage has occurred from the air conditioner 100, and the process ends. After that, the control device 30 executes, for example, a refrigerant leakage reporting function, which will be described later.

[Principle of refrigerant leak detection function]
Next, the principle of the refrigerant leakage detection function will be described.
First, the refrigerant sealed in the refrigerant circuit of the air conditioner 100 according to the embodiment is a non-azeotropic refrigerant mixture. A non-azeotropic refrigerant mixture is composed of a plurality of types of refrigerants having different boiling points. For example, R454B refrigerant, which is a non-azeotropic refrigerant mixture, is a mixture of R32 refrigerant and R1234yf refrigerant. The boiling point of R32 refrigerant at atmospheric pressure is −57.1 [° C.], and the boiling point of R1234yf refrigerant at atmospheric pressure is −29.4 [° C.]. When there is a difference in the boiling points of the refrigerants constituting the non-azeotropic mixed refrigerant in this way, when refrigerant leakage occurs from the air conditioner 100, there is a tendency that a larger amount of R32 refrigerant with a low boiling point is released outside the system. .

Therefore, the ratio of the refrigerant that constitutes the non-azeotropic refrigerant mixture that is enclosed in the refrigerant circuit of the air conditioner 100 differs depending on whether there is refrigerant leakage or not. The physical properties of the non-azeotropic refrigerant mixture present in the apparatus 100 will change. The refrigerant leakage detection function utilizes changes in the physical properties of the non-azeotropic mixed refrigerant caused by this refrigerant leakage.

A more detailed explanation of the principle of the refrigerant leak detection function will be given below. Generally, when the air conditioner 100 is stopped, the refrigerant in the refrigerant circuit and the outside air at the location where the outdoor unit 1 is installed are in a state of thermal equilibrium. The saturated temperature calculated from the refrigerant pressure in the second stage is equal to the outside air temperature.

However, when a refrigerant leak occurs, the physical property values of the non-azeotropic mixed refrigerant change as described above. It changes depending on the presence or absence of refrigerant leakage. Therefore, the principle of the refrigerant leakage detection function is to detect the presence or absence of refrigerant leakage by detecting the pressure difference in the refrigerant circuit when the air conditioner 100 is stopped.

Taking the case of the R454B refrigerant as an example, when there is no refrigerant leakage, the R32 refrigerant and the R1234yf refrigerant are 68.9 [wt%] and 31.1 [wt%] in the refrigerant circuit of the air conditioner 100. %]. On the other hand, when refrigerant leakage occurs, if the composition change due to refrigerant leakage is α (> 0), the refrigerant circuit of the air conditioner 100 contains R32 refrigerant and R1234yf refrigerant (68.9-α) [wt %] and (31.1+α) [wt %]. In other words, when refrigerant leakage occurs, the composition of R32 refrigerant with a low boiling point is reduced.

In the state where the refrigerant composition changes due to refrigerant leakage, the physical property values of the non-azeotropic refrigerant mixture also change. For example, the saturation pressure at a certain temperature also changes.

For example, when the outside air temperature is 35 [° C.], if there is no refrigerant leakage and the air conditioner 100 is stopped, the outside air and the outdoor unit 1 are in thermal equilibrium. Therefore, the pressure in the refrigerant circuit is 2.0 [MPaA], which is the saturation pressure of the R454B refrigerant at 35 [°C]. On the other hand, when a refrigerant leak occurs, the outside air and the outdoor unit 1 at the same temperature (35 [° C.]) are thermally balanced, but the composition of the R454B refrigerant is reduced by the composition change α. , R1234yf refrigerant is increased by the composition change α, the pressure in the refrigerant circuit is different even if the outside air temperature is the same, 35[°C]. In the case of this example, the composition of the R32 refrigerant is reduced, so the pressure is lower than 2.0 [MPaA] when no refrigerant leakage occurs.

The control device 30 has the relationship between the pressure and the saturation temperature in the filling composition of the non-azeotropic refrigerant in the form of a table or an approximate expression, and from the pressure detected by the discharge pressure detection device 20 or the suction pressure detection device 21, If the calculated saturation temperature does not match the outside air temperature, it can be determined that a refrigerant leak has occurred.

That is, in steps S1 to S3 shown in FIG. 5, it is determined whether or not the outside air and the outdoor unit 1 are thermally balanced, and in steps S4 to S6, the difference between the saturation temperature caused by the refrigerant leakage and the outside temperature is determined. It is a mechanism to calculate and detect the occurrence of refrigerant leakage.

In addition, the amount of decrease in saturation pressure when refrigerant leakage occurs depends on the type of non-azeotropic refrigerant used in the air conditioner 100, the size of the refrigerant circuit of the air conditioner 100, and how much refrigerant is outside the system. It is difficult to determine the predetermined value in step S5 shown in FIG.

If the predetermined value in step S5 in FIG. 5 for determining the presence or absence of refrigerant leakage is set to a small value, even a small amount of refrigerant leakage can be detected, but the thermal balance between the outside air and the outdoor unit 1 is insufficient. In some cases, or due to the measurement error of the pressure detection device or the outside air temperature detection device 22, there is a possibility that the refrigerant leak determination may be erroneous. Conversely, if the predetermined value in step S5 is set to a large value, the risk of erroneous determination of refrigerant leakage is reduced, but there is also a demerit such as the presence of refrigerant leakage cannot be determined unless the amount of refrigerant leakage from the air conditioner 100 increases. . Therefore, it is necessary to change the predetermined value in step S5 depending on the type of refrigerant used, the size of the refrigerant circuit of the air conditioner 100, how much refrigerant has leaked outside the system, and the like. Moreover, since the predetermined value in step S5 is also affected by the installation state of the air conditioner 100, it is preferable to allow adjustment even on site after the installation work is completed.

Here, the predetermined value in step S5 will be supplemented by taking the case of R454B refrigerant as an example. There is an R454C refrigerant composed of the same constituent refrigerant as the R454B refrigerant, and the R454C refrigerant is a refrigerant in which the R32 refrigerant and the R1234yf refrigerant are mixed at a mass ratio of 21.5 [wt%] and 78.5 [wt%]. . Taking the case of an outside air temperature of 7 [°C] as an example, the saturated vapor pressure of R454B refrigerant is 0.91 [MPaA], while the saturated vapor pressure of R454C refrigerant at the same outside temperature of 7 [°C] is 0.91 [MPaA]. 57 [MPaA]. This pressure of 0.57 [MPaA] corresponds to the saturation temperature of -8.1 [°C] for the R454B refrigerant.

That is, with the R454B refrigerant, when the air conditioner 100 is stopped under the condition that the outside air temperature is 7 [° C.], if there is no refrigerant leakage, the detection value of the discharge pressure detection device 20 indicates that the saturation temperature of the refrigerant is 7 [°C]. On the other hand, if there is a refrigerant leak, the R32 refrigerant is released into the atmosphere before the R1234yf refrigerant, and the refrigerant composition is the same as the R454C refrigerant, the value detected by the discharge pressure detection device 20 indicates that the refrigerant is saturated. The temperature becomes -8.1 [°C]. Therefore, in the case of the present embodiment, even if the predetermined value in step S5 is set to 1[° C.], the refrigerant leakage can be sufficiently detected.

In addition, in order to improve the detection accuracy of the refrigerant leakage detection function, it is preferable to use the outside air temperature detection device 22 with higher detection accuracy than other temperature detection devices. Similarly, at least one of the discharge pressure detection device 20 and the suction pressure detection device 21 with high detection accuracy should be used as the pressure detection device, and the detection value thereof should be used to determine refrigerant leakage.

Regarding the determination of whether or not the outside air and the outdoor unit 1 are in thermal equilibrium in steps S2 and S3 in FIG. It may be the time until the detection value of the discharge pressure detection device 20 and the detection value of the suction pressure detection device 21 mounted in the unit become the same. Further, since the accuracy of refrigerant leakage determination is improved when the detection value of the outside air temperature detection device 22 in step S3 is stable, whether or not the outside air temperature detected by the outside temperature detection device 22 is stable is determined. For example, it is preferable that the outside air temperature change is 1° C. or less per hour.

Even when a single-component refrigerant is sealed in the refrigerant circuit of the air conditioner 100, when refrigerant leakage occurs, the pressure in the refrigerant circuit decreases, and it may be possible to determine the refrigerant leakage from the detected value of the pressure detection device. However, in a large-scale air-conditioning equipment such as a building multi-system equipped with an accumulator 13, excess refrigerant exists in the refrigerant circuit in a liquid state, and the pressure in the refrigerant circuit is likely to decrease due to refrigerant leakage. Then, the surplus refrigerant evaporates to become gas refrigerant, thereby suppressing pressure drop in the refrigerant circuit. For this reason, the pressure in the refrigerant circuit does not easily change until all the surplus refrigerant existing in the liquid state evaporates. Detecting refrigerant leaks using refrigerant pressure is difficult.

On the other hand, when a non-azeotropic refrigerant mixture is enclosed in the refrigerant circuit of the air conditioner 100, when the accumulator 13 is mounted, the liquid-phase surplus refrigerant evaporates in the refrigerant circuit as in the case of the single-component refrigerant. Although it is difficult to reduce the pressure of the refrigerant mixture, a large amount of the refrigerant with a low boiling point among the constituent refrigerants of the non-azeotropic refrigerant mixture leaks out of the system. change) occurs, and refrigerant leakage can be detected even with a small amount of refrigerant leakage.

Since the refrigerant leakage detection function according to the present embodiment is based on the principle of using the boiling point difference of the non-azeotropic refrigerant, the accumulator 13 is an essential component in the air conditioner 100 using the non-azeotropic refrigerant mixture. Refrigerant leakage can be detected by the operation shown in FIG. 5 even if there is no accumulator 13 .

The control device 30 also has a daily inspection function that executes a refrigerant leakage detection function every predetermined time (hereinafter also referred to as a preset second time). With this daily inspection function, it is possible to determine whether the refrigerant leak has occurred during an intermediate period such as spring or autumn when the air conditioner 100 is not in operation, or even at night. Therefore, it is possible to check whether or not refrigerant leakage occurs every day or every few days, so that refrigerant leakage can be detected early. In addition, refrigerant leakage can be detected wherever the refrigerant leakage occurs.

The control device 30 also has a refrigerant leakage notification function that notifies the occurrence of refrigerant leakage when it is determined that there is a refrigerant leakage by executing the refrigerant leakage detection function. Refrigerant leakage is reported by, for example, a buzzer or the like, or if a centralized control device or the like is connected to the air conditioner 100, an alert to the effect that a refrigerant leak has been detected is issued to the centralized control device. For example, the inspection of the air conditioner 100 is prompted. By doing so, it is possible to inform the equipment manager of the occurrence of the refrigerant leakage early, and it is possible to quickly take appropriate measures such as repairing the equipment.

In addition, in conventional air conditioners that use flammable refrigerant, etc., by installing a refrigerant leakage detection device in the indoor unit or in the air-conditioned space where the indoor unit is installed, the safety of the room due to refrigerant leakage is ensured. Although this method is commonly used, it has the problem that refrigerant leaks cannot be detected in spaces where no refrigerant leak detection device is installed, such as rooms with large floor areas or above ceilings.

In order to solve this problem, the refrigerant to be used must be a non-azeotropic mixed refrigerant, but by using the refrigerant leakage detection function according to the present embodiment, it is possible to detect refrigerant leakage from places where there is no refrigerant leakage detection device. It is possible to improve the safety on the indoor side.

Further, in the case where the air conditioner 100 is equipped with a safety device such as an alarm device, a ventilator, and a shut-off device specified by international standards such as ISO5149 or IEC60335-2-40, the present embodiment can be used. If the above-described safety device is activated when it is determined that there is a refrigerant leakage by the refrigerant leakage detection function, it is possible to further improve the safety of the indoor side.

In the air conditioner 100 according to the present embodiment, all the

indoor units

2a and 2b operate in the same manner, that is, only one of the cooling operation mode and the heating operation mode. , different operation may be performed for each of the

indoor units

2a and 2b, that is, the cooling operation mode and the heating operation mode may be performed at the same time.

Also, in the present embodiment, the case where the number of outdoor units 1 is one has been described as an example, but the number of outdoor units 1 is not limited to one. The operation of the refrigerant leakage detection function shown in FIG. is not limited, in the case of a large air conditioning system configured with a plurality of outdoor units 1, the refrigerant leakage detection function may be operated for each outdoor unit 1, or one of the plurality of outdoor units 1 may be set as a representative, and the representative outdoor unit 1 may perform the operation of the refrigerant leakage detection function.

In addition, in the air conditioner 100 according to the present embodiment, the case where the outdoor unit 1 is provided with one compressor 10 has been described as an example, but it is not limited to this, and the outdoor unit 1 is provided with a compressor 10. Two or more machines 10 may be provided.

As described above, the air conditioner 100 according to the embodiment includes a refrigerant circuit in which the compressor 10, the heat source side heat exchanger 12, the expansion device 41, and the load side heat exchanger 40 are connected in order by pipes. An air conditioner 100 in which a non-azeotropic mixed refrigerant is sealed as a refrigerant, and detects the pressure of the refrigerant on the discharge side of the compressor 10, or detects the pressure of the refrigerant on the suction side of the compressor 10. A first pressure detection device, an outside temperature detection device 22 that detects the outside temperature, and the pressure detected by the first pressure detection device and the outside temperature detected by the outside temperature detection device 22 when the air conditioner 100 is stopped. and a control device 30 having a refrigerant leakage detection function for determining presence/absence of refrigerant leakage based on the above.

According to the air conditioner 100 according to the embodiment, when the air conditioner 100 is stopped, refrigerant leakage is detected based on the pressure detected by the first pressure detection device and the outside temperature detected by the outside temperature detection device 22. Presence/absence is determined. Therefore, refrigerant leakage can be detected throughout the year regardless of the season, and the occurrence of refrigerant leakage from the air conditioner can be detected regardless of the operating state of the air conditioner.

In addition, in the conventional technology, for the purpose of ensuring the safety of the air-conditioned space where the indoor unit is installed, even if a refrigerant leak occurs in a large space, the refrigerant leaks when the refrigerant concentration in the air-conditioned space is not high, or There are some that do not target refrigerant leaks from refrigerant pipes that exist in non-air-conditioned spaces such as ceiling spaces. However, the air-conditioning apparatus 100 according to the embodiment can detect refrigerant leakage wherever the refrigerant leakage occurs.

In addition, in the conventional technology, there is a technique in which a plurality of shutoff valves are provided in an air conditioner, and a refrigerant leak point is identified by detecting a pressure drop in a section closed by the shutoff valves. However, since the air conditioner 100 according to the embodiment does not require a plurality of shutoff valves, the manufacturing cost can be reduced.

Also, the air conditioner 100 according to the embodiment includes an accumulator 13 on the suction side of the compressor 10 .

According to the air conditioner 100 according to the embodiment, since the accumulator 13 is provided on the suction side of the compressor 10, the refrigerant composition variation (change in physical property value) occurs, and refrigerant leakage is detected even with a small amount of refrigerant leakage. can do.

In addition, the air conditioner 100 according to the embodiment includes a temperature detection device in addition to the outside air temperature detection device 22, and the outside air temperature detection device 22 has higher detection accuracy than the temperature detection device.

According to the air conditioner 100 according to the embodiment, detection accuracy of the refrigerant leakage detection function can be improved.

In addition, the air conditioner 100 according to the embodiment includes a pressure detection device in addition to the first pressure detection device, and the first pressure detection device has higher detection accuracy than the pressure detection device.

In addition, in the air conditioner 100 according to the embodiment, the control device 30 has a daily inspection function that executes a refrigerant leakage detection function every second preset time.

According to the air conditioner 100 according to the embodiment, it is possible to determine the refrigerant leakage even in the middle of spring or autumn when the air conditioner 100 is not in operation, or at night, by means of this daily inspection function. Therefore, it is possible to check whether or not refrigerant leakage occurs every day or every few days, so that refrigerant leakage can be detected early. In addition, refrigerant leakage can be detected wherever the refrigerant leakage occurs.

In addition, in the air conditioner 100 according to the embodiment, the control device 30 executes the refrigerant leakage detection function, and notifies the occurrence of refrigerant leakage when it is determined that there is refrigerant leakage.

According to the air conditioner 100 according to the embodiment, when it is determined that there is a refrigerant leak, the occurrence of the refrigerant leak is reported, so that the equipment manager can be notified early that the refrigerant leak has occurred. Appropriate measures such as repair of equipment can be quickly taken.

1 outdoor unit, 2, 2a, 2b indoor unit, 3 refrigerant main pipe, 4a, 4b refrigerant branch pipe, 5 refrigerant pipe, 10 compressor, 11 refrigerant flow switching device, 12 heat source side heat exchanger, 13 accumulator, 14 heat source side blower, 20 discharge pressure detection device, 21 suction pressure detection device, 22 outside air temperature detection device, 23 first temperature detection device, 30 control device, 40, 40a, 40b load side heat exchanger, 41, 41a, 41b expansion device , 42, 42a, 42b Load side blower 50, 50a, 50b Second

temperature detection device

51, 51a, 51b Third

temperature detection device

52, 52a, 52b Fourth

temperature detection device

60a, 60b Air-conditioned space 61 Space above the ceiling, 100 air conditioner.

Claims

An air conditioner comprising a refrigerant circuit in which a compressor, a heat source side heat exchanger, a throttling device, and a load side heat exchanger are sequentially connected by piping, and a non-azeotropic refrigerant mixture is sealed as a refrigerant in the refrigerant circuit. and
a first pressure detection device that detects the pressure of the refrigerant on the discharge side of the compressor or detects the pressure of the refrigerant on the suction side of the compressor;
an outside temperature detection device for detecting outside temperature;
Control having a refrigerant leakage detection function for determining whether or not a refrigerant leak exists based on the pressure detected by the first pressure detection device and the outside air temperature detected by the outside air temperature detection device when the air conditioner is stopped. An air conditioner comprising:
Regarding the refrigerant leakage detection function,
The control device is
The presence or absence of refrigerant leakage is determined by comparing the saturation temperature of the refrigerant obtained from the pressure detected by the first pressure detection device and the outside air temperature detected by the outside air temperature detection device. air conditioner.
Regarding the refrigerant leakage detection function,
The control device is
The air conditioner according to claim 1 or 2, wherein the presence or absence of refrigerant leakage is determined after a first time set in advance has elapsed since the air conditioner was stopped.
Regarding the refrigerant leakage detection function,
The control device is
4. The air according to claim 3, wherein the presence or absence of refrigerant leakage is determined when the outside air temperature detected by the outside air temperature detection device is stable after the first time has elapsed since the air conditioner stopped. Harmony device.
The air conditioner according to any one of claims 1 to 4, further comprising an accumulator on the suction side of the compressor.
In addition to the outside air temperature detection device, a temperature detection device is provided,
The air conditioner according to any one of claims 1 to 5, wherein the outside air temperature detection device has higher detection accuracy than the temperature detection device.
In addition to the first pressure detection device, a pressure detection device is provided,
The air conditioner according to any one of claims 1 to 6, wherein the first pressure detection device has higher detection accuracy than the pressure detection device.
The control device is
The air conditioner according to any one of claims 1 to 7, further comprising a daily inspection function that executes the refrigerant leakage detection function every second time set in advance.
The control device is
The air conditioner according to any one of claims 1 to 8, wherein the refrigerant leakage detection function is executed, and when it is determined that there is refrigerant leakage, occurrence of refrigerant leakage is notified.